This is a study of infant feeding practices among Bedouin tribes residing in the Negev, Israel. The objectives are: the evaluation of changes in infant feeding practices during the first year of life and their relationship to physical growth of children and on gastrointestinal and respiratory diseases during the first year of life. The information obtained covers 5,000 mother-infant pairs. Two samples have been identified, one was identified at birth and a subsample of these births was followed for a period of 5-8 months. Another sample of children was identified at 6 months of age and followed prospectively to 18 months of age. Several aspects of the data from this project have been analyzed. These include an analysis of the seasonality of births in the Bedouin population showing the preponderance of births in the winter months and a trough in the summer months and possible explanations for the seasonality, determinants of infant feeding practices at birth including socio-demographic characteristics, obstetrical characteristics including complications during pregnancy and around the time of births and conditions in the child during the first two days of life. Other analyses deal with the study of the relationship of infant feeding practices during the first year of life and physical growth during the first year of life. Characteristically this population of Bedouin infants shows an increasing level of stunting during the second half of the first year of life. Part of this is related to the practice of extending exclusive breastfeeding beyond six months of age without any food supplementation.